The present invention relates generally to a fluid pump and more particularly relates to a fluid concentrate pump for use in disposable concentrate packages.
Post mix juice dispensers generally include a disposable concentrate container, a concentrate pump, and a dispensing nozzle. Known dispensers generally positioned the concentrate pump within the dispenser itself. Due to the requirements of cleaning and servicing the pump, however, that portion of the pump that contacts the concentrate later became part of the disposable concentrate package itself. In use, the operator removes the exhausted concentrate container, replaces it with a new or a different container, and then proceeds to dispense the beverage. No cleaning of the pump or the dispenser generally is required.
Although these known dispensers are in widespread use, there are several perceived drawbacks with the existing designs. For example, the components used in these xe2x80x9cdisposablexe2x80x9d containers and pumps may be relatively expensive. As such, it may be cost prohibitive to produce the pumps and containers on a large scale even if these components may be easy to use.
Further, the pulsation produced in some of these known devices may be objectionable to certain consumers. Specifically, the sound produced by a pulsating pump may be annoying. More importantly, these pumps may not produce a consistent beverage in that the pumps may tend to deliver the concentrate in pulses or lumps of material. This lumping may prevent adequate mixing of the concentrate and the water or other liquid. This inadequate mixing may result in a beverage with an off taste.
What is needed, therefore, is a pump that provides a consistently smooth flow of concentrate. This smooth flow must be provided in a disposable pump and container that is reasonably priced and compatible with existing dispensing equipment.
The present invention thus provides a pump for delivering product from a product package to a nozzle. The pump may include a housing with a first port, a second port, and an interior. The first port mates with the product package and the second port mates with the nozzle. A first check valve may be positioned within the first port. A piston rod may be positioned within the interior of the housing for movement therein. The piston rod may include a first piston and a second piston. The first piston may include a second check valve positioned therein such that the product is forced past the first check valve on a down stroke of the piston rod and forced past the second check valve on an up stroke of the piston rod.
Specific embodiments of the present invention may include the housing having an upper housing and a lower housing. The housing and the piston rod may be made out of a thermoplastic material in an injection molding process. The housing further may include a third port for delivering a liquid. The third port may be positioned between the first piston and the second piston. The pistons each may have an O-ring positioned thereon for contact with the housing. The piston rod may move a distance of about 0.175 to about 0.325 inches (about 0.444 to 0.825 centimeters) within the housing, with about 0.25 inches (about 0.635 centimeters) preferred. The piston rod may cycle within the housing about three to six times a second.
The first check valve and the first piston may define a first cavity within the housing. The first cavity may include a volume of about 3.5 to about 6.5 milliliters. The first cavity may include a vacuum of about 0.7 to about 3.0 atmospheres when the first piston moves away from the first check valve. The first piston and the second piston may define a second cavity within the housing. The second cavity may be in communication with the second port. The second cavity may include a volume of about 1.75 to about 3.25 milliliters. The first check valve and the second check valve may have an opening pressure of about 2 to about 8 pounds per square inch (about 140.6 to 562.4 gf/cm2).
A further embodiment of the present invention may provide a pump for delivering product from a product package. The pump may include a housing with a first valve in communication with the product package and a piston rod positioned within the housing for movement therein. The piston rod may include a first piston and a second piston. The first piston may include a second valve therein such that the product is forced past the first check valve on a down stroke of the piston rod and forced past the second valve on an up stroke of the piston rod. The first chamber may include a volume of product of about twice the volume of the second chamber. The housing may include a nozzle port. The nozzle port may be positioned between the first and the second piston such that product is forced out of the nozzle port on both the down stroke and the up stroke of the piston rod.
The method of the present invention provides for delivering product with a pump from a product source to a nozzle. The pump may include a first valve and a piston rod with a first piston and a second piston. The first piston may include a second valve such that the first valve and the first piston define a first chamber and the second valve and the second piston define a second chamber. The method may include the steps of moving the piston rod in a downward direction, creating a vacuum in the first chamber so as to force the product from the product source through the first valve and into the first chamber, moving the piston rod in an upward direction, and compressing the product in the first chamber so as to force the product through the second valve and into the second chamber.
The method may further include the steps of moving the piston rod in the downward direction, creating a vacuum in the first chamber so as to force the product through the first valve and into the first chamber, and forcing an amount of the product in the second chamber into the nozzle. About 1.75 to 3.25 milliliters of the product may be forced into the nozzle during the down stroke. The method also may include the steps of moving the piston rod in the upward direction, compressing the product in the first chamber so as to force the product through the second valve and into the second chamber, and forcing an amount of the product in the second chamber into the nozzle. About 1.75 to about 3.25 milliliters of the product also may be forced into the nozzle during the up stroke.
Other objects, features, and advantages of the present invention will become apparent upon review of the following detailed description of the preferred embodiments of the invention when taken in conjunction with the drawings and the appended claims.